Reduced progranulin increases tau and α-synuclein inclusions and alters mouse tauopathy phenotypes via glucocerebrosidase

Comorbid proteinopathies are observed in many neurodegenerative disorders including Alzheimer’s disease (AD), increase with age, and influence clinical outcomes, yet the mechanisms remain ill-defined. Here, we show that reduction of progranulin (PGRN), a lysosomal protein associated with TDP-43 proteinopathy, also increases tau inclusions, causes concomitant accumulation of α-synuclein and worsens mortality and disinhibited behaviors in tauopathy mice. The increased inclusions paradoxically protect against spatial memory deficit and hippocampal neurodegeneration. PGRN reduction in male tauopathy attenuates activity of β-glucocerebrosidase (GCase), a protein previously associated with synucleinopathy, while increasing glucosylceramide (GlcCer)-positive tau inclusions. In neuronal culture, GCase inhibition enhances tau aggregation induced by AD-tau. Furthermore, purified GlcCer directly promotes tau aggregation in vitro. Neurofibrillary tangles in human tauopathies are also GlcCer-immunoreactive. Thus, in addition to TDP-43, PGRN regulates tau- and synucleinopathies via GCase and GlcCer. A lysosomal PGRN–GCase pathway may be a common therapeutic target for age-related comorbid proteinopathies.


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All studies must disclose on these points even when the disclosure is negative.In EPM test, outliers detected by ROUT (Q = 1%) were excluded because the animals were deemed to fail to be adapted to the test.In MWM, mice that took more than 30 s to reach the visible platform were excluded because they were deemed to have eye problems rather than memory problems or lack the motivation.The criteria were not pre-established, but similar criteria were used in our previous studies (Spurrier et al., Sci Transl Med, 2022;Tang et al., Acta Neuropathol Commun, 2020;Gunther et al., Cell Rep, 2019).No data were excluded in the other experiments.
For mouse experiments, all the biological replicates to support reproducibility are described in each figure legend.Mouse Morris water maze and elevated plus maze tests were performed with two independent cohorts and similar results were obtained.Immunohistochemical findings were verified by repeating the staining at least once with different antigen combinations in different experiments.Similar results were obtained in the replication staining experiments.Co-IP and GCase activity assays were performed to replicate previous publications as described in the manuscript.An increase in GlcCer levels in Grn-/-mice was confirmed by both lipidomics and immunohistochemistry.In addition, our results of lipidomic analysis are consistent with a previous publication (Logan et al., Cell, 2021).At least three independent experiments were performed in co-IP, AD-tau seeding, and Thioflavin T assays.At least two independent EM image sessions were conducted using independently prepared samples to confirm reproducibility.All attempts at replication were successful.
Animals were grouped based on their genotype.Primary cultured neurons for AD-tau seeding assay and tau protein for ThT assay were randomly allocated into experimental groups.

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April 2023

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Plants provided in in Supplementary Fig. 1. 1.For volumetric, immunohistochemcal, and biochemical analyses, only male were used as as previous studies have reported significantly more tau pathology and neurodegeneration in in male versus female PS19 mice (Leyns et et al., 2017;Shi et et al., 2017;Wu Wu et et al., 2019;Yanamandra et et al., 2013) This study did not involve samples collected from the field.
All protocols were approved by by Yale Institutional Animal Care and Use Committee (IACUC) (2023-07281).
n/a n/a n/a Samples of pre-existing human autopsy brain with no personal identifiers were obtained from Harvard Brain Tissue Resource Center, Banner Sun Health Research Institute, and Vancouver General Hospital.Sample size of AD-tau seeding assay was determined based on our previous studies(Tang et al., Acta Neuropathol Commun, 2020; Neis et al., JBC, 2021).Sample size of ThT assay was determined based on previous publications(Mazzulli et al., Cell, 2011; Briner et al., Cell Rep, 2020; Chakraborty et al.,  Nat Commun, 2021).Sample size of co-IP assay was determined based on our previous study(Klein et al.Neuron, 2017).
There were no human subject participants.The human tissue was obtained from pre-existing autopsy tissue with no personal identifying information and deemed exempt from human subjects regulation by the Yale Institutional Review Board.Sample size of experiments using mice was determined based on previous studies including ones using PS19 or Grn-/-mice(Spurrier et al., Sci  Transl Med, 2022; Logan et al., Cell, 2021; Tang et al., Acta Neuropathol Commun, 2020; Zhou et al.PLoS One, 2019; Shi et al., JEM, 2019;  Klein et al., Neuron, 2017; Shi et al., Nature, 2017; Takahashi et al., Acta Neuropathol, 2017; Leyns et al., PNAS, 2017).